Genetic responses of the ark shell Scapharca broughtonii Schrenck to environmental shock: High temperatures and long exposure times

Abstract

Genetic responses of non-high temperature exposed and high temperature exposed ark shell (Scapharca broughtonii) cells collected from Dukyang Bay in August 2007 to environmental shock have been compared. In the analysis of two-dimensional electrophoresis, seven protein spots were found. They have no matching protein in the database, but the number of protein (#1) in unstressed ark shells differed from that of stressed ark shells, indicating a strong signal on the gel and had a homology with arginine kinase (molecular weight, 38 kDa; pI 8.3). The predicted tertiary structure of arginine kinase formed finger-like antiparalled b-sheet projections. A small a-helical N-terminal domain is followed by a larger C-terminal domain. Extracted total RNA was reverse transcribed and amplified by PCR with primer used in this study. Mantle, gill and visceral in non-high temperature exposed ark shell showed some levels of arginine kinase transcripts, but not the foot. These cells also showed amplified fragments on the gel exposed to 20 °C, 23°C and 27°C, but the foot cell had no expression of arginine kinase gene at 27°C for 3 hrs. These findings provide important insights into the possible molecular mechanisms in which no expression of arginine kinase is contributed to preventing the binding of arginine and actin and difficult to move foot muscle.